2007+ SI-DRIVE and Boost Control

[viriix]

Ever since I saw Louey's HKS EVC V it's made me want one... I was stopped for a moment when doubts were clouded whether it would work or not.. which was somewhat de-moralising and dissapointing because of concerns potentially with the SI-DRIVE..

There have been mixed opinions and I don't think we still have anyone who's got one.. yet..

I can hardly find information on any other forums but.. bumped into this article from a dealership in Canada;

http://www.dexterssubaru.com/NewsDetail02.asp?ArticleID=2724&OwnerID=&WebPageID=4749&WebSiteID=179

3/4 down the page you will see

"How SI-DRIVE Works" and

Turbocharger boost and AVCS operation remain unaffected with SI-DRIVE

Hmm interesting.. I'm thinking perhaps it's time to give it a go? That definately makes me feel a bit more confident!

C'mon Phil hurry up!

[moggy]

Thanks for the link, that's a very interesting read.


Bob.

[07GTSTi]

yeah... I want a boost controller.

[EXPLICIT]

More than likely its a fueling and timing map that varies on each I-drive selection. So in theory the amount of boost you 'tune' when in S# mode won't affect any of the lessor settings. Having said that if you're stretching the friendship with the engines boost threshold with plenty of fuel and timing to match it 'could' be a concern when commuting on full boost in Intelligent mode. Tuning the boost controller with a dyno and afr readouts would be recommended.

Once the ecu has been cracked and we begin to tune it, the very nature if the SI-Drive will become apparent.

[MY07GT]

Nice work Aj.

Well once my exhaust is sorted, hopefully this weekend. The hks evc will be the first thing in! Got it waiting at PHAT's house.

Phil.

[sleepergtb]

From what I have expereinced, standard I modes runs 7 PSI and S and S# 13.5 PSI.

There are already tuners out there will a good understanding of SI Drive and how it has been tuned/achieved.

I am not convinced that you will not get inconsistent result and or codes being thrown going methods other than the tuning route. Time will tell however I suppose.

[07GTSTi]

I would say that getting the boost controller at the same time as a tune would be the best option.
If it all holds together in S#, there shouldn't be any problems with other modes, running less advance, etc.

[sleepergtb]

I would say that getting the boost controller at the same time as a tune would be the best option.
If it all holds together in S#, there shouldn't be any problems with other modes, running less advance, etc.

this is good advice and is what I did, I mode now runs 10PSI and is more usable day to day.

[viriix]

makes sense..

I'll sit back and see how it goes with phil

[MY07GT]

makes sense..

I'll sit back and see how it goes with phil

Bastard! Let me be the guinea pig why dontcha!

Well once i find time to drop off my car to have the exhaust sorted, the evc will be on after that!

Phil.

[Resonate]

Nice find.

I bet alot of us will be interested to see how it turns out.

[yipming]

The SI-Drive control boost indirectly I reckon. Since max boost would need full throttle to create enough exhaust pressure to push the turbine. By simply restricting throttle the max boost should theoretically drop too. So the article saying SI-Drive dont actually manipulate boost/avc would make sense. Since to the car, "I" mode is simply electronically forced light footed driver.

But Subaru uses MAP rather than AFM though, a tune would be needed rather than a simple wastegate bypass valve. Unlike Nissans... Otherwise the A/F ratio would be thrown completely off.


Hmm ... obviously I reserved the right to be completely wrong. =P

[MY07GT]

Only time will tell people. I dont think anyone is willing to take that risk to find out.... except for my stoopid ass.

Phil.

[07GTSTi]

To my limited understanding, the Si-Drive is a subfeature of the ECU, for cerain parameters ie. throttle control, ignition and fuel. Boost control is still a feature, but not altered with the different Si-Drive settings.

So when you get a reflash of the ecu, you should be able to increase the amount of boost, in the same way that previous models have.

So then, the main advantage of an aftermarket EBC (when already having a tune) is adjustability and the ability to have separate low/high boost settings.

Chances are I'm wrong though.

[LIBIDO]

makes sense..

I'll sit back and see how it goes with phil

mate i reckon u should pay royalties to Phil for his trial and error!!